I take Mircette, and I skipped taking one of the inactive pills one time (if you take the generic Kariva, it's the green pills that are inactive). You are really supposed to take the rest of the active pills in the last row though! They just have lower hormones instead of being totally inactive, so it probably could mess up your period if you skip these!

I take kariva (generic mircette) and i actually looked up the brand name mircette on the FDA website to find out what the deal was with the half-strength estrogen pills. Its a complicated FDA approval file, but from what I understand is that the company thought that half-strength pills (the blue ones in my kariva) would "improve cycle control" and "reduce escape ovulations due to pills missed, because of a reduced pill-free interval", but neither ended up being true. Another thing, it said that women who were taking mircette had a higher incidence of a lack of withdrawal bleeding or only spotting, than women who were taking estrogen-free placebos. But the company wasn't trying to prove(or advertise) there would be shorter periods so no statistics were calculated.

Bottom line: Taking them or not really doesn't matter, you don't need to take them the next day if you forget to take one. But, they recommend that you take all the pills in the pack, so you start the next pack on time. For me, sometimes I take them, sometimes I don't, i don't notice anything different.

Side note: There is another oral contraceptive that will be coming out soon, that has lower dose estrogen during the pill free week. Its called Seasonique. It's exactly the same as seasonale, except for that last week.